Isoform-specific phosphoinositide 3-kinase inhibitors as therapeutic agents

The phosphoinositide 3-kinase (PI3K) family of enzymes consists of several closely related isoforms that are thought to have distinct biological roles. Until now, researchers have been frustrated by poor selectivity of the available pharmacological inhibitors, which are unable to distinguish adequately the activities of different PI3K isoforms. Recently published patent specifications describe new PI3K inhibitors, including several that are selective for the PI3Kdelta isoform. There is now cautious optimism that isoform-selective PI3K inhibitors will provide new avenues for therapeutic applications in a range of diseases.     

Polar lipids in human meibomian gland secretions

PURPOSE: To determine the polar lipid composition of human meibomian gland secretions and their relationship to the preocular tear film. METHODS: Meibomian secretions were collected from normals and patients with chronic blepharitis. These lipids (meibum) were first separated by thin layer chromatography. Polar lipids were then separated utilizing high-pressure liquid chromatography with ultraviolet detection. Individual peaks were identified by comparison with standards. Collected sample peaks were subjected to differential transmethylation with sodium methoxide-methanol and the resulting fatty acid methyl esters were analyzed by gas chromatography-mass spectroscopy. RESULTS: Three phospholipids were identified as phosphatidylcholine, phosphatidylethanolamine and sphingomyelin; other unidentified phospholipids were also present. Also present in secretions were the sphingolipids ceramides and cerebrosides. Fatty acids present were 12-18 carbon chain length. All fatty acids were normal (not branched) saturated fatty acids except in sphingolipids, where hydroxy fatty acids were also present. Unsaturated normal fatty acids were present only in meibum from patients with meibomianitis. CONCLUSIONS: The composition of the polar lipids in meibomian gland secretions is more complex than previously thought. On the other hand, the type and carbon chain length of the polar lipid fatty acids appears strictly controlled. The relationship of these findings to the preocular tear film should be considered in terms of overall functionality. The polar lipid layer most likely is only one to three molecules thick and serves as a surfactant between aqueous tears and the thicker nonpolar lipid layer.     

Meibomian gland function and the tear lipid layer

The meibomian glands of the lid produce a lipid material whose synthesis is dependent on neuronal, hormonal, and vascular factors. This lipid material is fluid, spreads easily, is a surfactant as well as an aqueous barrier and must remain functional after a blink. To satisfy these requirements, the meibomian lipids have a specific composition. Even after delivery it may be modified by lipases produced by ocular bacteria, and modifications in the lipid components can lead to unique disease states. For example, bacteria may degrade lipids, producing an unstable tear film and irritating free fatty acids; and hormonal imbalances may alter lipid profiles to destabilize the tear film and produce evaporative dry eye.     

Beta-funaltrexamine affects cocaine self-administration in rats responding on a progressive ratio schedule of reinforcement

Many studies have shown interactions between mu-opiates and the mesolimbic dopamine (DA) system. Mu-opiate receptor antagonists have been reported to either increase or decrease the rate of cocaine self-administration, and the interpretation of these data has been difficult. In an attempt to further characterize and localize the effect of opiate receptor blockade on the reinforcing effects of cocaine, the mu-opiate irreversible antagonist beta-funaltrexamine (betaFNA) was administered locally to different regions of the mesocorticolimbic system. Microinjection of betaFNA into the ventral tegmental area (VTA) or the nucleus accumbens (NAcc) had no effect on cocaine self-administration under a fixed ratio (FR) schedule of reinforcement. However, blockade of opiate receptors in both brain regions did attenuate responding for cocaine maintained by a progressive ratio (PR) schedule. Administration of betaFNA in the dorsal striatum had no effect under either schedule condition. The present findings suggest that endogenous opiate systems within the mesolimbic DA system modulate the reinforcing effects of cocaine; however, this modulation seems to be schedule dependent.     

Regulation of granulocyte apoptosis by hemopoietic growth factors, cytokines and drugs: potential relevance to allergic inflammation

It has become apparent that the resolution of inflammation depends on the removal of unwanted inflammatory cells, a process governed by physiological apoptosis and non-inflammatory clearance of apoptotic cells. Granulocytes are central to many of the pathophysiological consequences of uncontrolled inflammatory reactions. Hemopoietic factors and cytokines play a critical role in regulating the longevity of these cells in vitro and in vivo. Here we review the progress that has been made in the understanding of granulocyte apoptosis and the implications for immunotherapy and pharmacological strategies in the treatment of allergic inflammatory diseases for therapeutic gain.     

Acculturation and overweight-related behaviors among Hispanic immigrants to the US: the National Longitudinal Study of Adolescent Health

Little is known about the factors underlying the striking increase in overweight occurring between first and second generation US immigrants. Using data from the National Longitudinal Study of Adolescent Health, this study addressed two goals. First, we determined which measures of acculturation (defined as the acquisition of dominant cultural norms by members of a non-dominant group) were important. Second, we determined how the acculturation process affected differences in overweight and its proximate determinants (e.g., physical activity, diet, and smoking) as immigrants acculturated to American society. In addition, we sought to elucidate the role of underlying structural factors (e.g., family income and crime) and acculturation factors (e.g., language spoken at home and proportion of foreign-born neighbors) in generation differences in overweight. Results showed clear structural and acculturation differences between foreign and US-born immigrants to the US. Foreign-born immigrants were more likely to have lower family income and maternal education, and to live in areas of higher immigrant density and greater linguistic isolation. In addition, results suggested rapid acculturation of overweight-related behaviors, such as diet, smoking, and inactivity, in US-born relative to foreign-born immigrants. Multivariate analysis indicated that longer US residence was associated with increased overweight among Puerto Ricans and Cubans. Predicted probabilities showed that controlling for acculturation and proximate factors increased overweight among foreign-born adolescents, but had minimal impact for US-born adolescents. Thus, without the beneficial pattern of: acculturation factors, diet, and physical activity, first generation Hispanic adolescents would have higher overweight prevalence. We found important generation differences in structural, acculturation, and proximate overweight determinants. These lifestyle differences between foreign- and US-born Hispanic adolescent immigrants are likely to underlie the striking increase in overweight prevalence between first and subsequent generation of US residence.     

Dying for work: The magnitude of US mortality from selected causes of death associated with occupation

BACKGROUND: Deaths due to occupational disease and injury place a heavy burden on society in terms of economic costs and human suffering. METHODS: We estimate the annual deaths due to selected diseases for which an occupational association is reasonably well established and quantifiable, by calculation of attributable fractions (AFs), with full documentation; the deaths due to occupational injury are then added to derive an estimated number of annual deaths due to occupation. RESULTS: Using 1997 US mortality data, the estimated annual burden of occupational disease mortality resulting from selected respiratory diseases, cancers, cardiovascular disease, chronic renal failure, and hepatitis is 49,000, with a range from 26,000 to 72,000. The Bureau of Labor Statistics estimates there are about 6,200 work-related injury deaths annually. Adding disease and injury data, we estimate that there are a total of 55,200 US deaths annually resulting from occupational disease or injury (range 32,200-78,200). CONCLUSIONS: Our estimate is in the range reported by previous investigators, although we have restricted ourselves more than others to only those diseases with well-established occupational etiology, biasing our estimates conservatively. The underlying assumptions and data used to generate the estimates are well documented, so our estimates may be updated as new data emerges on occupational risks and exposed populations, providing an advantage over previous studies. We estimate that occupational deaths are the 8th leading cause of death in the US, after diabetes (64,751) but ahead of suicide (30,575), and greater than the annual number of motor vehicle deaths per year (43,501).     

GP and patient predictors of PSA screening in Australian general practice

OBJECTIVE: We determined GP and patient variables associated first with men's prior uptake of prostate-specific antigen (PSA) screening and, subsequently, its initiation during an 'index consultation' in Australian general practice. METHODS: From the practices of 60 GPs, we recruited a sample of 423 male patients aged 40-70 years. In a waiting room questionnaire completed before their 'index consultation' (retrospective component), men reported their previous PSA screening status. We obtained demographic and clinical data, including the presence of lower urinary tract symptoms (LUTS). Men also were mailed a questionnaire 2 days after their 'index consultation' to ascertain whether the GP had discussed PSA screening (prospective component) for prostate cancer and other behaviours. GPs themselves completed questionnaires eliciting demographic and practice characteristics as well as their propensity to screen and understanding of the evidence about PSA testing. GP and patient study variables were modelled simultaneously in analyses. RESULTS: Of those 348 men consulting with their regular GP, 80 (23.0%) reported previously having had a PSA screening test. Men were significantly and independently more likely ever to have had PSA screening if their regular GP reported a propensity to initiate screening [adjusted odds ratio (AOR) = 2.27, 95% confidence interval (CI) 1.23-4.20; P = 0.009]. GP age also was independently associated with men's PSA screening status [chi-squared (3) P < 0.0001] as was men's age and severity of LUTS (AOR = 2.38, 95% CI 1.58-3.57, P < 0.0001 and AOR = 1.79, 95% CI 1.00-3.19, P = 0.004, respectively). Current smokers were less likely ever to have had a PSA screening test (AOR = 0.34, 95% CI 0.16-0.69; P = 0.003). Discussion of PSA screening in their 'index consultation' was recalled independently more often by older men (AOR = 1.46, 95% CI 1.00-2.13; P = 0.04), those with moderate/severe LUTS (AOR = 1.94, 1.07-3.49; P = 0.04), those whose GP had performed or discussed a cholesterol test (AOR = 2.26, 95% CI 1.03-4.92; P = 0.04) and those whose GP had postgraduate training in family medicine (AOR = 3.13, 95% CI 1.23-8.00; P = 0.02). CONCLUSION: In the absence as yet of compelling evidence that PSA screening will prolong life or enhance its quality, our findings identify GP and patient factors that could be targeted to modify PSA screening.     

Functional mapping of protective epitopes within the rotavirus VP6 protein in mice belonging to different haplotypes

We recently used "functional mapping" to locate protective epitopes in the carboxyl terminus (aa 197-397) of the VP6 protein (designated CD) of the EDIM strain of murine rotavirus [J. Virol. 74 (2000) 11574]. For this, H-2(d) BALB/c mice were given two intranasal (i.n.) immunizations (separated by 2 weeks) with VP6 or CD genetically-fused to maltose-binding protein, or with overlapping synthetic CD peptides, along with LT(R192G), a genetically-attenuated E. coli heat-labile toxin. The protective efficacies, i.e., percentage reductions in rotavirus shedding relative to control mice during 7 days following oral challenge with EDIM, were determined 4 weeks after the second immunization. Five of the 11 overlapping CD peptides stimulated significant protection (57-85%, P<0.05). Furthermore, chimeric VP6, the CD fragment, and a 14-amino-acid VP6 peptide within CD (RLSFQLMRPPNMTP), identified as a H-2(d)-restricted CD4 T cell epitope, were highly protective (93-98%, P<0.05). In this study, we continued to utilize functional mapping to show that the 14-mer peptide elicited significant protection (97.0%, P<0.05) in another H-2(d) mouse strain (DBA/2) but partial protection in H-2(b) 129 (39.2%) and C57Bl/6 (53.6%) as well as H-2(k) C3H (44.6%) mice. The first 13 amino acids of this 14-mer were necessary to induce maximal protection in H-2(d) mice. In addition, the H-2(b) 129 mice were immunized intranasally (i.n.) with 10 of the synthetic CD peptides and 5 were found to induce significant protection (90-97%, P<0.05). We also performed functional mapping to identify MHC class I epitopes in rotavirus proteins. A class I-binding epitope for H-2(b) C57Bl/6 mice had previously been mapped by ex vivo CTL assays within the VP6 protein and two additional class I epitopes were identified by computer-based prediction. When examined for their protective efficacies by functional mapping, two of the three were found to be partially but not significantly protective (44 and 46%, P>0.05). To better determine the usefulness of our in vivo methods to identify MHC class I-binding epitopes, four epitopes from the outer capsid VP7 rotavirus protein determined in ex vivo assays were evaluated for their protective efficacies and two were found to be partially protective. Together, these studies show that functional mapping is useful in locating epitopes that are relevant to the development of subunit rotavirus vaccines.